1. Field of the Invention
This invention relates to carillon type tone generator instruments and, more particularly, to carillon keyboard instruments for providing automatic or operator controlled Flemish bell tones.
2. Description of the Prior Art
Various musical instruments have been built and available to the public over the years for playing bell or chime tones, such instruments being adapted particularly for uses in churches, university bell towers and the like. Conventionally, in such instruments the nature of the bell tone is essentially fixed in the instrument, such as the tone produced by the striking of a foundry-cast bell is fixed in its essential nature. In bell instruments and other types of electronic musical instruments, various techniques have been utilized to modify the tone, such as producing undulating sounds and the like, but such procedures do not alter the essential nature of the bell tone. The utilization of bars or rods, either solid or hollow, for the purpose of striking same and generating vibrations which are translated into electrical signals by suitable transducers, is known in the art of making bell or carillon type instruments. But again, the produced tones are essentially unalterable. The fundamental reason for this is that once the vibrator bar is produced and mounted, and a means for initiating vibration is likewise fixed in position, the essential nature of the resulting vibrations is fixed.
In the area of carillon type instruments, it is a primary aim to generate signals which are accurately representative of Flemish tuned bells. The Flemish tuned bell has a very distinct sound which is recognized immediately as being characteristic, or representative of a bell. The tuned bell, of traditional origin, does not produce a natural music tone, but rather a tone which contains partials which set it off as having a sound quite distinct from all other musical notes. The partials of the tuned bell were selected after much experimentation over the years in seeking a bell sound that would be pleasing in its harmonic and partial combinations. In particular, it is the combination of the individual partials produced in the vibration of the bell that gives the tuned bell its characteristic sound. Although the tuning of bells has long been carried out as an exacting art, there are still many harmonic combinations which are dissonant to listeners, and the tuning of carillon bells has long been controversial. Thus, it is the arrangement of the partials produced when a bell or vibrating bar is struck which gives the bell tone its characteristic sound. The relative strength of the minor partials and major partials, with the resulting dissonance, is a subjective matter with which carilloneurs have always and presumably always will have differences. To illustrate, strike tone C and E-natural form a major third interval, while strike tone C and its first partial E-flat form a minor third interval. A strong minor-second clash exists between E-natural and E-flat, because the minor third partial is very prominent. By reducing the "loudness", or strength, of the minor partial and increasing the loudness, or strength, of the major partial, a more consonant sound is produced. Conversely, reducing the loudness, or strength of the major partial, and increasing the loudness, or strength of the minor partial, produces a more dissonant sound. However, the presence of the minor partial is necessary for a bell to have its characteristic sound. The amount in relation to the major partial may vary, but both the major and minor partials are necessary for production of a bell tone. The prior art contains a great deal of descriptive literature concerning the partial and harmonic makeup of bell tones, and it is not intended in this specification to set forth those teachings. However, it is sufficient for an understanding of this invention to keep in mind that the term major partials, or simply majors, refers to a first combination of frequencies, whereas the term minor partials or minors refers to a second distinct combination, and that the desired bell tone for any one given bell sound is some combination of these two.